High Pressure Relief Valve Piston

ABSTRACT

In one featured embodiment, a piston for a valve comprises a cylindrical body surrounding a center axis and defined by an overall length extending from an upstream end to a downstream end. The cylindrical body has a piston bore configured to receive a spring assembly. The cylindrical body has a maximum outer diameter that comprises a closure sleeve contact surface, and the cylindrical body is defined by a first length that is less than the overall length. A ratio of the first length to the maximum outer diameter is between 1.0 and 1.2.

BACKGROUND OF THE INVENTION

This application relates to a high pressure relief valve which may be utilized in a fuel control for an aircraft engine.

A fuel system provides fuel to various portions of a gas turbine engine. The fuel system includes a fuel pump and a High Pressure Relief Valve (HPRV) that supplies fuel to the gas turbine engine.

Should the fuel system experience a blockage, pressure will build up in the system. The HPRV allows fuel pressure to be relieved from a location downstream of the pump, with the fuel then being returned to a pump inlet. The HPRV is essential to safe operation of a fuel pumping unit and is designed to relieve excessive pressure and prevent catastrophic failure of the fuel pump and main housing. The existing high pressure relief valves may sometimes result in undesirably high pressure losses.

Performance of the HPRV is critical to seamless operation of the fuel delivery system.

SUMMARY OF THE INVENTION

In one exemplary embodiment, a piston for a valve comprises a cylindrical body surrounding a center axis and defined by an overall length extending from an upstream end to a downstream end. The cylindrical body has a piston bore configured to receive a spring assembly. The cylindrical body has a maximum outer diameter that comprises a closure sleeve contact surface, and the cylindrical body is defined by a first length that is less than the overall length. A ratio of the first length to the maximum outer diameter is between 1.0 and 1.2.

In another exemplary embodiment, the cylindrical body includes first and second outer surface portions that are axially spaced apart from each other and which are both defined by the maximum outer diameter. The cylindrical body includes an undercut portion providing a central outer surface portion that is between the first and second outer surface portions. The undercut portion is defined by an undercut outer diameter, and a ratio of the undercut outer diameter to the maximum outer diameter is between 0.8 and 1.0.

In another exemplary embodiment, a boss portion is formed at the upstream end of the cylindrical body and encloses one end of the piston bore leaving an opposite end of the piston bore open to receive the spring assembly. The boss portion comprises a seat for a pivoting half ball, with the seat comprising a conical surface formed within the boss portion and being defined by a conical angle. The conical angle is within a range between 100 and 120 degrees.

In another exemplary embodiment, a high pressure relief valve comprises a valve housing defining an internal bore and having a valve inlet configured to be in fluid communication with a pump outlet. A closure sleeve is at least partially received within the internal bore, and comprises a sleeve body surrounding a center axis. The sleeve body has an internal cavity that is enclosed at the downstream end and is open at the upstream end. A piston is received within the internal cavity, wherein the internal cavity is defined in part by a piston contact surface. The piston comprises a cylindrical body surrounding a center axis and is defined by an overall length extending from an upstream end to a downstream end. The cylindrical body has a piston bore configured to receive a spring assembly, and the cylindrical body has a maximum outer diameter that comprises a closure sleeve contact surface. A nozzle is received within the internal bore of the valve housing and includes a nozzle bore having a nozzle inlet in fluid communication with the valve inlet and a nozzle outlet. A spring assembly biases the piston to close the nozzle outlet, and when a system pressure at the nozzle outlet exceeds a predetermined pressure level, a spring biasing load is overcome to open the nozzle outlet to fluidly connect the nozzle to the internal cavity of the closure sleeve. The high pressure relief valve includes one or more of the following valve characteristics: wherein the cylindrical body portion is defined by a first length that is less than the overall length, and wherein a ratio of the first length to the maximum outer diameter is between 1.0 and 1.2; wherein the cylindrical body includes first and second outer surface portions that are axially spaced apart from each other and which are both defined by the maximum outer diameter, and including an undercut portion providing a central outer surface portion that is between the first and second outer surface portions, the undercut portion being defined by an undercut outer diameter, and wherein a ratio of the undercut outer diameter to the maximum outer diameter is between 0.8 and 1.0; wherein the piston includes a boss portion formed at the upstream end of the cylindrical body, the boss portion enclosing one end of the piston bore leaving an opposite end of the piston bore open to receive the spring assembly, and wherein the boss portion comprises a seat for a pivoting half ball, the seat comprising a conical surface formed within the boss portion and being defined by a conical angle, and wherein the conical angle is within a range between 100 and 120 degrees; wherein the boss portion is defined by a boss outer diameter, and wherein the seat comprises a conical opening defined by the conical surface, and wherein the conical opening is defined by a depth extending from an apex of the conical surface to an end face of the boss portion, and wherein a ratio of the depth to the boss outer diameter is between 0.3 and 0.4; wherein the sleeve body includes at least one damping orifice defined by a damping orifice diameter, and wherein the cylindrical body of the piston includes at least one vent window defined by a vent window diameter, and wherein a ratio of the damping orifice diameter to the vent window diameter is between 0.375 and 0.450.

These and other features may be best understood from the following drawings and specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic view of a fuel system for an aircraft.

FIG. 2 is a cross-sectional view of the high pressure relief valve of FIG. 1.

FIG. 3 a perspective view of the closure sleeve and nozzle from the high pressure relief valve of FIG. 2.

FIG. 4 is an assembled view for the components of FIG. 3.

FIG. 5 is a section view through the closure sleeve.

FIG. 6 is a side view of the closure sleeve.

FIG. 7 is a section view through the nozzle of FIG. 3.

FIG. 8 is a magnified view of a nozzle face as identified in FIG. 7.

FIG. 9 is a section view through a piston of the high pressure relief valve of FIG. 2.

FIG. 10 is a perspective view of the piston.

FIG. 11 is a section view of a spring seat of a spring assembly as shown in FIG. 2.

FIG. 12 is a perspective view of the spring seat of FIG. 11.

FIG. 13 is a section view of a disc of a spring assembly as shown in FIG. 2.

FIG. 14 is an end view of the disc of FIG. 13.

DETAILED DESCRIPTION

FIG. 1 shows a schematic view of an aircraft fuel supply system 20 having a fuel pump 22 drawing fuel from a fuel supply 24. The pump 22 has a pump inlet 26 in fluid communication with the fuel supply 24 and a pump outlet 28 is in fluid communication with a high pressure relief valve (HPRV) 30. During normal operating conditions the HPRV 30 remains closed and the fuel passes through a filter to remove contaminants. Fuel exiting the filter is then directed to fuel metering system 32 with a fuel metering valve 34 to supply fuel to an engine 36. If the supply of fuel at the fuel metering system 32 is excessive for the current engine operating condition the excess fuel is ported back to the pump inlet 26.

The HPRV 30 is positioned immediately downstream of the pump outlet 28. Should the system 20 become clogged or blocked, the pressure will become undesirably high, which could result in damage to the pump 22 or pump housing 36. The HPRV 30 will automatically open once a specified pressure level is exceeded to allow fuel to return to the pump inlet 26.

A cross-sectional view of the HPRV 30 is shown in FIG. 2. The HPRV 30 is comprised of a valve housing 40 aligned longitudinally along a valve center axis A, a closure sleeve 42 received within the valve housing 40, a piston 44 received within the closure sleeve 42, a nozzle 46, and a spring assembly 48 that biases the HPRV 30 to the closed position. The spring assembly 48 includes a spring 50, a spring seat 52, a ball 54, and a washer or disc 56. A half ball 58 is positioned axially between one end of the piston 44 and the nozzle 46.

The closure sleeve 42 and nozzle 46 are shown in greater detail in FIGS. 3-5. The closure sleeve 42 comprises a one-piece component that is configured to include a HPRV assembly with the HPRV 30 while also providing an end cap closure. This configuration reduces the overall number of components for the HPRV 30.

As shown in FIG. 3, the closure sleeve 42 has an upstream end 60 and a downstream end 62. The upstream end 60 is received within an internal bore or cavity 64 (FIG. 2) of the valve housing 40 and the downstream end 62 extends outwardly of the valve housing 40. The closure sleeve 42 defines an internal cavity 66 (FIG. 5) within which the spring assembly 48 and piston 44 are received. The downstream end 62 of the closure sleeve 42 is enclosed such that when the closure sleeve 42 is mounted within the valve housing 40, the HPRV 30 is sealed. As shown in FIG. 2, a seal 68 is positioned radially between an inner surface 70 of the valve housing 40 and an outer surface 72 of the closure sleeve 42 at a downstream end 74 of the valve housing 40 to ensure that the internal cavities 64, 66 are sealed from leaking externally.

As shown in FIG. 5, the internal cavity 66 is defined in part by an inner surface 76 that directly abuts against an outer surface 78 of the piston 44 in a sliding relationship. The inner surface 76 of the closure sleeve 42 is defined by an inner diameter ID_(C) and a piston engagement sleeve length L₁ (FIG. 5). The outer surface 78 of the piston 44 is defined by an outer diameter OD_(P) (FIG. 9). The outer diameter OD_(P) comprises the maximum outer diameter of the piston 44. As shown in FIG. 5, the flange 80 extends radially outwardly of the closure sleeve 42, which abuts against the downstream end 74 of the valve housing 40 (FIG. 2). A notch or groove 82 is formed within the outer surface of the closure sleeve 42 immediately upstream of the flange 80. The seal 68 (FIG. 1) is received within the groove 82.

The closure sleeve 42 includes one or more vent or damping orifices 84 (FIG. 6) that extend through a thickness of the closure sleeve 42 from the inner surface to the outer surface of closure sleeve 42. The damping orifice 84 is defined by a diameter D_(D). The damping orifice 84 is in fluid communication with an annulus 86 (FIG. 2) that is formed radially between the closure sleeve 42 and the valve housing 40. The annulus 86 is in fluid communication with a separate pressure input P_(I). The damping orifice 84 facilitates slowing down, i.e. controlling how fast the valve can move. A seal 88 (FIG. 2) is positioned radially between the valve housing 40 and the closure sleeve 42. The seal 88 is seated within a notch 89 (FIG. 5) formed within the closure sleeve 42. This seal 88 allows the pressure input P_(I) to be independent of the pressure outlet P_(d). The internal cavity 66 of the closure sleeve 42 comprises a spring cavity that receives the spring assembly 48. Pressure within the spring cavity is the same as the pressure input P_(I).

The closure sleeve 42 includes a plurality of windows 90 (FIG. 3) that are circumferentially spaced apart from each other about the closure sleeve 42 adjacent the upstream end 60. Each window 90 is defined by a window diameter D_(w) (FIG. 5). The windows 90 are in fluid communication with the internal cavity 64 (FIG. 2) of the valve housing 40 at the pressure outlet Pd. Once system pressure P_(S) is greater than the biasing force of the spring assembly 48 (spring load) plus the spring cavity pressure, the half ball 58 is unseated from the nozzle 46 and the spring assembly 48 moves to the left, i.e. downstream, which allows fluid to flow through the windows 90 and exit the pressure outlet P_(d). The exiting fluid is then returned to the pump inlet 26.

The closure sleeve 42 also includes a pair of slots 92 (FIG. 3) formed in the upstream end 60. In one example, the slots 92 are spaced one hundred and eighty degrees apart from each other. The slots 92 are defined by a slot width S_(W) and a slot depth or length S_(L) (FIGS. 5-6). The slots 92 receive corresponding tabs 94 (FIGS. 3 and 7) that are on the nozzle 46 as best shown in FIG. 4. After the tabs 94 are inserted into the slots 92 a snap ring 96 fits in a groove 98 in the closure sleeve 42 to prevent the closure sleeve 42 and nozzle 46 from separating from each other. The snap ring 96 is shown positioned externally on the closure sleeve 42 for this configuration; however, it can also be incorporated on an inner diameter ID of the closure sleeve 42 to achieve the same retention of the nozzle 46.

The inner diameter that defines the internal cavity 66 of the closure sleeve 42 is sized to accommodate the HPRV spring assembly 48. The outer diameter that defines the outer surface of the closure sleeve 42 is sized, relative to the bore (internal cavity 64) of the valve housing 40, to minimize pressure drop in the bore of the valve housing 40. The closure sleeve 42, thus, optimizes flow through the HPRV 30 while also providing containment of valve components in a cartridge type design. The windows 90 are configured to minimize pressure drop through the HPRV 30 while regulating the pressure acting on the piston 44. The windows are also positioned to minimize hydraulic side loading of the piston 44.

In one embodiment, the inner diameter ID_(C) of the closure sleeve 42 at the engagement surface with the piston 44 is 1.0 inches (2.54 centimeters) and the interface length L₁ of the closure sleeve 42 is 1.3 inches (3.30 centimeters). In embodiments, a ratio of the interface length L₁ to the inner diameter IDc is between 1.0 and 1.5.

In one embodiment, the closure sleeve 42 has a slot width S_(W) of 0.4 inches (1.02 centimeters) and the inner diameter ID_(C) is 1.0 inches (2.54 centimeters). In embodiments, a ratio of the slot width S_(W) to the inner diameter ID_(C) is between 0.1 and 0.6.

The slot length S_(L) is 0.25 inches (0.635 cm) and a slot width S_(W) is 0.4 inches (1.02 centimeters). A ratio of slot width S_(W) to slot length S_(L) is between 1.0 and 2.5. In one embodiment, the window diameter D_(W) is 0.35 inches (0.89 centimeters) and the outer diameter OD_(P) of the piston 44 at the engagement surface to the sleeve 42 is 1.0 inches (2.54 centimeters). In embodiments, a ratio of the window diameter D_(W) to the outer diameter OD_(P) of the piston 44 is between 0.3 and 0.5.

In one embodiment, the diameter D_(D) of damping orifice 84 is 0.032 inches (0.08 centimeters) and the inner diameter ID_(C) is 1.0 inches (2.54 centimeters). In embodiments, a ratio of the diameter D_(D) of the damping orifice 84 to the inner diameter ID_(C) is between 0.020 and 0.050.

In one embodiment, a length L_(x) from a center of the windows 90 to a depth face 100 of the slot 92 is within the range of 0.09 inches (0.23 centimeters) to 0.44 inches (1.12 centimeters).

The nozzle 46 is shown in greater detail in FIGS. 3-4 and 7. The nozzle 46 controls the inlet flow and balances momentum forces against the spring load. The nozzle 46 includes a nozzle bore 101 (FIG. 7) that extends from an inlet end 102 to an outlet end 104. The nozzle 46 is defined by an overall nozzle length L_(N) that extends from the inlet end 102 to the outlet end 104. The inlet end 102 is in fluid communication with an inlet bore 103 (FIG. 2) of the valve housing 40 that receives fluid at the system pressure P_(S).

The nozzle 46 is defined by an outer surface 106 that extends from the inlet end 102 to an upstream side of the tabs 94. This outer surface 106 is defined by a generally constant nozzle outer diameter OD_(N). The tabs 94 are defined by a tab outer diameter that is greater than the nozzle outer diameter OD_(N). The nozzle 46 also includes a tapering outer surface portion 108 that extends from a downstream side of the tabs 94 to the outlet end 104.

The outlet end 104 provides an outlet end face 110 (FIG. 8), i.e. nozzle face, that is defined by an outlet outer diameter OD_(O) and an outlet inner diameter ID_(O) that are radially spaced apart from each other by a radial distance R_(N1) (FIG. 8) to define an annular thickness at the outlet end face 110. The annular outlet end face 110 contacts a generally flat end face 112 of the half ball 58 when the HPRV 30 is in the closed position.

The inlet end 102 of the nozzle 46 provides an inlet end face 114 (FIG. 7) that is defined by an inlet outer diameter OD_(I) and an inlet inner diameter ID_(I) that are radially spaced apart from each other by a radial distance R_(N2) to define an annular inlet end face 114. The inlet inner diameter ID_(I) is greater than an inner diameter D_(H) of the valve housing 40 at the inlet bore 103. This configuration prevents pressure loss at this location.

The outer surface 106 of the nozzle 46 includes a groove 116 that receives a seal with slipper 118 (FIG. 2). This seal is provides sealing between the valve housing 40 and the nozzle 46.

The nozzle bore 101 includes at least a first bore section B1 (FIG. 7) and a second portion section B₂. The first bore section B₁ is defined by a generally constant diameter (corresponding to the outlet inner diameter ID_(O)) that extends along a first bore section length L_(B1). The first bore section length L_(B1) extends from the outlet end face 110 to a position 120 within the nozzle bore 101. In one example, the position 120 is located upstream of the tabs 94.

The second bore section B₂ comprises a conical section that has a variable diameter. The second bore section B₂ is defined by a second bore section length L_(B2) that extends from the position 120 to the inlet end face 114. The second bore section B₂ has a smallest diameter (corresponding to the outlet inner diameter ID_(O)) at the position 120 and a largest diameter (corresponding to the inlet inner diameter ID_(I)) at the inlet end face 114. The second bore section B₂ increases in diameter in a generally constant manner from the position 120 to the inlet end face 114 such that the second bore section is defined by a conical surface angle A_(N).

In one embodiment, at the nozzle face, i.e. the outlet end face 110, the nozzle 46 has an outlet inner diameter ID_(O) that is 0.280 inches (0.711 centimeters) and an outlet outer diameter OD_(O) that is 0.297 inches (0.754 centimeters). In embodiments, a ratio of the outlet inner diameter ID_(O) to the outlet outer diameter OD_(O) is between 0.95 and 0.98.

In one embodiment, the outlet inner diameter ID_(O) is 0.280 inches (0.711 centimeters) and the first bore section length L_(B1) is 0.290 inches (0.737 centimeters). The ratio of the outlet inner diameter ID_(O) at the nozzle face to the first bore section length L_(B1) is between 0.80 and 1.10.

In one embodiment, the outlet inner diameter ID_(O) is 0.280 inches (0.711 centimeters) and the overall nozzle length L_(N) is 1.055 inches (2.680 centimeters). The ratio of the outlet inner diameter ID_(O) at the nozzle face to the overall nozzle length L_(N) is between 0.30 and 0.25.

In one embodiment, the conical surface angle A_(N) of the nozzle 46 is within a range between 0 degrees and 25 degrees.

The nozzle 46 is sized to handle the required flow while meeting system requirements for performance. The nozzle 46 is configured to reduce pressure drop, off-centered flow, and flow swirling. The larger diameter at the inlet to the nozzle is sized to align with the valve housing inlet plumbing line. The smaller nozzle diameter is sized to balance momentum loads to minimize valve droop. The nozzle length is sized to allow a 20 degrees transition “cone” from the plumb line inlet diameter to the smaller nozzle outlet diameter. In one example, the smaller nozzle diameter, i.e. the outlet inner diameter ID_(O), is sized to maintain a diameter to length ratio of 1.0.

The piston 44 is shown in greater detail in FIGS. 9-10. The piston 44 comprises a cylindrical body portion 130 with an upstream end 132 and a downstream end 134. A piston bore 136 is formed within the cylindrical body portion 130 to receive the spring assembly 48 (FIG. 2). The bore is defined by an inner diameter ID_(P). A boss portion 138 is formed at the upstream end 132 to serve as a seat for the half ball 58 (FIG. 2). The boss portion 138 encloses one end of the piston bore 136 leaving the opposite end open to receive the spring assembly 48.

The piston 44 has a maximum outer diameter OD_(P) which forms the outer surface 78 that abuts against the closure sleeve 42. One portion of this abutment surface 78 is formed at the downstream end 134 and another portion of this abutment surface 78 is formed at the upstream end 132. These two portions are axially separated from each other by an undercut portion having an outer surface 140 that is defined by an outer diameter OD_(R) that is less than the maximum outer diameter OD_(P). This outer surface 140 is spaced radially inwardly of an inner surface of the closure sleeve 42 to form an annulus 142 between the sleeve 42 and piston 44 (FIG. 2).

One or more vent windows 144 (FIG. 9) are formed within the piston 44. The vent windows are defined by a vent diameter D_(V) and extend through a thickness of the piston 44 from the outer surface 140 to the piston bore 136. The vent windows 144 fluidly connect the spring cavity 66 with the annulus 142 (FIG. 2). The annulus 142 is in fluid communication with the damping orifice 84 formed in the closure sleeve 42, which is in fluid communication with the annulus 86. The vent windows 144 are sized based on the size of the damping orifice 84 in the closure sleeve 42. The vent windows 144, annulus 142, damping orifice 84, and annulus 86 cooperate with each other to control movement of the valve to reduce pressure losses.

The piston 44 is defined by an overall length L_(P), the cylindrical body portion 130 is defined by a length L_(E), and the boss portion 138 is defined by a length L_(B). The boss portion 138 includes a conical opening 146 (FIG. 9) that is defined by a conical surface 148 that serves as a seat for the half ball 58. The conical surface 148 is defined by a conical angle α_(c). The depth of the conical opening 146 from the apex of the conical surface 148 to the end face of the boss portion 138 is defined by a length L_(C).

As shown in FIG. 2, the half ball 58 is semi-hemispherical in shape and has a substantially flat surface 112 that faces the nozzle 46 and a spherical surface 150 that sits in the conical opening 146. The spherical surface 150 cooperates with the conical surface 148 to allow pivoting movement of the hall ball 58 such that the nozzle face can be fully sealed in the closed position even if the piston and nozzle are not fully in axial alignment with each other.

In one embodiment, the length L_(E) of the cylindrical body portion 130 that includes the outer surface portions 78, 140 is 1.13 (2.870 centimeters) and the maximum outer diameter OD_(P) is 1.00 inches (2.54 centimeters). The ratio of the length L_(E) of the cylindrical body portion 130 to the maximum outer diameter OD_(P) is between 1.0 and 1.2.

In one embodiment, the damping orifice diameter D_(D) in the closure sleeve 42 is 0.032 (0.081 centimeters) and the vent window diameter D_(V) is 0.078 inches (0.198 centimeters). The ratio of the damping orifice diameter D_(D) to the vent window diameter D_(V) is between 0.375 and 0.45.

In one embodiment, the outer diameter OD_(R) of the undercut portion having surface 140 is 0.954 inches (2.423 centimeters) and the maximum outer diameter OD_(P) is 1.0 inches (2.54 centimeters). The ratio of the outer diameter OD_(R) of the undercut portion having the surface 140 to the maximum outer diameter OD_(P) is between 0.8 and 1.0.

In one embodiment, the conical angle α_(c) of the boss portion 138 is within a range of between 100 degrees and 120 degrees.

In one embodiment, the depth or length L_(C) of the conical opening 146 in the boss portion 138 is 0.277 inches (0.704 centimeters) and the maximum diameter OD_(C) of the boss portion 138 with the conical opening 146 is 0.850 inches (2.159 centimeters). The ratio of the length L_(C) of the conical opening 146 to the maximum diameter OD_(C) of the boss portion 138 is between 0.3 and 0.4.

As shown in FIG. 2, the piston 44 provides the conical seat for the half ball 58 as well as the pressure area internal to the closure sleeve 42. The seat is sized to hold the half ball 58 and allows for ball rotation. The piston maximum outer diameter OD_(P) (FIG. 9) is sized for a pressure area to meet valve performance requirements. The internal annulus is sized to provide a ten times area increase over the spring cavity damping orifice 84. The vent windows 144 in the piston 44 are sized to a ten times area increase over the spring cavity damping orifice 84. The number of windows is optimized to vent air in any orientation of the piston 44.

As discussed above, the spring assembly 48 (FIG. 2) includes the spring seat 52, the ball 54, the disc 56, and the spring 50. The spring seat 52 is shown in greater detail in FIGS. 11-12 and the disc 56 is shown in greater detail in FIGS. 13 and 14. The spring seat 52 comprises a cup-shaped body 160 with a recess 162 for seating the ball 54. The recess 162 is defined by a maximum inner diameter ID_(M). The ball 54 is defined by a ball diameter D (FIG. 1). The base of the cup-shaped body 160 has an opening 164 into the piston bore 136, and thus is fluidly connected to the spring cavity 66. The cup-shaped portion 160 is defined by a maximum outer cup diameter D_(C) and a length L_(S). The opening 164 facilitates seating of the ball 54 within the cup-shaped portion 160.

The spring seat 52 fits within the piston bore 136. The spring seat 52 includes an enlarged flange portion 166 with an outer edge 168 that slides against an inner surface of the piston bore 136. The outer edge 168 is defined by a maximum outer diameter OD_(M) of the spring seat 52.

As shown in FIGS. 13-14, the disc 56 has a thickness T that extends from an upstream side 170 to a downstream side 172 of the disc 56. The disc 56 is defined by an outer diameter OD and has a center opening 174 that is defined by an inner diameter ID.

In one example, the piston 44 is made from an aluminum material while the ball 54 is comprised of a steel material. The disc 56 is also comprised of a steel material. The disc 56 is tightly fit within the piston 44 and is positioned axially between an end face of the piston bore 136 and the ball 54 to keep the ball 54 from contacting the piston 44.

As shown in FIG. 2, the spring 50 has a first end 178 that is seated against an end face of the closure sleeve 42 and a second end 180 that is seated against the flange portion 166 of the seat 52. The spring end 180 surrounds the cup-shaped portion 160. The spring 50 is defined by a spring inner diameter IS and a coil diameter C. As known, springs do not always push in a completely straight line. The ball 54 allows the spring seat 52 to rotate around the ball by approximately 8 degrees until the upper or lower edge 168 of the flange portion 166 contacts the disc 56.

In one example, the outer diameter OD of the disc 56 is 0.837 inches (2.126 centimeters) and the inner diameter ID_(P) of the piston 44 is 0.85 inches (2.159 centimeters). The ratio of the outer diameter OD of the disc 56 to the inner diameter ID_(P) of the piston 44 is between 0.97 and 0.99.

In one example, the inner diameter ID of the disc 56 is 0.192 inches (0.488 centimeters) and the diameter D of the ball 54 is 0.312 inches (0.792 centimeters). The ratio of the inner diameter ID of the disc 56 to the diameter D of the ball 54 is between 0.60 and 0.95.

In one example, the thickness T of the disc 56 is 0.06 inches (0.152 centimeters) and the outer diameter OD of the disc 56 is 0.837 inches (2.126 centimeters). The ratio of the thickness T of the disc 56 to the outer diameter OD of the disc 56 is between 0.06 and 0.08.

In one example, the inner diameter ID_(M) of the spring seat 52 is 0.316 inches (0.803 centimeters) and the diameter D of the ball 54 is 0.312 inches (0.792 centimeters). The ratio of inner diameter ID_(M) of the spring seat 52 to the diameter D of the ball 54 is between 1.01 and 1.10.

In one example, the maximum outer diameter OD_(M) of the spring seat 52 is 0.710 inches (1.803 centimeters) and the inner diameter ID_(P) of the piston 44 is 0.85 inches (2.159 centimeters). The ratio of maximum outer diameter OD_(M) of the spring seat 52 to the inner diameter ID_(P) of the piston 44 is between 0.8 and 0.9.

In one example, the maximum axial distance between the seat 52 and the disc 56 (FIG. 2) is approximately two times the nominal spacing between the seat 52 and the disc 56. The nominal spacing is shown in FIG. 2 as the axial distance between the seat 52 and disc 56 when both components are aligned with each other. If the upper or lower edge 168 of the seat 52 contacts the disc 56. The furthest distance, i.e. the maximum axial distance, at the non-contacting edge 168 is no more than two times the nominal spacing.

In one example, the maximum length L_(s) of the cup-shaped portion 160 is 60-100% of a coil diameter of the spring 50.

In one example, the outer diameter Dc of the cup-shaped portion 160 is 0.439 inches (1.115 centimeters) and the inner diameter IS of the spring 50 is 0.459 inches (1.166 centimeters). The ratio of outer diameter Dc of the cup-shaped portion 160 to the inner diameter IS of the spring 50 is between 0.901 and 0.98.

In one example, the outer diameter Dc of the cup-shaped portion 160 is 0.439 inches (1.115 centimeters) and the length L_(S) of the cup-shaped portion 160 is 0.092 inches (0.234 centimeters). The ratio of outer diameter Dc of the cup-shaped portion 160 to the length L_(S) of the cup-shaped portion 160 is between 4.0 and 5.0.

The spring assembly 48 serves to remove side-loading from the HPRV 30. The seat 52 is sized to hold the ball 54, with the seat walls being sized to handle the spring loads and ball contact stress. The disc outer diameter OD is sized to align with the piston inner diameter ID_(P), which reduces shucking of the seat assembly. The disc inner diameter ID is size for the ball size and to accommodate contact stresses. The disc thickness T is sized to ensure that the ball 54 never contacts the piston 44. The ball 54 is sized to fit into the seat 52 while optimizing pivoting and minimizing contact stresses. In one example, the assembly is configured to allow for approximately 8 degrees of rotation.

In a method of replacing a piston 44, nozzle 46, spring assembly 48, or closure sleeve 42 in a HPRV 30, at least one of the piston 44, nozzle 46, spring assembly 48 or closure sleeve 42 is removed from the valve housing 40, and at least one of a replacement piston, nozzle, spring assembly, or closure sleeve replaces the removed piston, nozzle, spring assembly, or closure sleeve. The piston, nozzle, spring assembly, or closure sleeve which is replaced is generally as disclosed above.

With a valve made according to the above description, the pressure losses across the valve are dramatically reduced and the operating is improved when compared to the prior art.

Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention. 

1. A piston for a valve comprising: a cylindrical body surrounding a center axis and defined by an overall length extending from an upstream end to a downstream end, wherein the cylindrical body has a piston bore configured to receive a spring assembly, and wherein the cylindrical body has a maximum outer diameter that comprises a closure sleeve contact surface, and wherein the cylindrical body is defined by a first length that is less than the overall length, and wherein a ratio of the first length to the maximum outer diameter is between 1.0 and 1.2.
 2. The piston according to claim 1, wherein the cylindrical body includes first and second outer surface portions that are axially spaced apart from each other and which are both defined by the maximum outer diameter, and includes an undercut portion providing a central outer surface portion that is between the first and second outer surface portions, the undercut portion being defined by an undercut outer diameter, and wherein a ratio of the undercut outer diameter to the maximum outer diameter is between 0.8 and 1.0.
 3. The piston according to claim 1, including a boss portion formed at the upstream end of the cylindrical body, the boss portion enclosing one end of the piston bore leaving an opposite end of the piston bore open to receive the spring assembly, and wherein the boss portion comprises a seat for a pivoting half ball, the seat comprising a conical surface formed within the boss portion and being defined by a conical angle, and wherein the conical angle is within a range between 100 and 120 degrees.
 4. The piston according to claim 3, wherein the seat comprises a conical opening defined by a conical surface formed within the boss portion, and wherein the conical opening is defined by a depth extending from an apex of the conical surface to an end face of the boss portion, and wherein a ratio of the depth to the boss outer diameter is between 0.3 and 0.4.
 5. A piston for a valve comprising: a cylindrical body surrounding a center axis and defined by an overall length extending from an upstream end to a downstream end, wherein the cylindrical body has a piston bore configured to receive a spring assembly, and wherein the cylindrical body has a maximum outer diameter that comprises a closure sleeve contact surface, wherein the cylindrical body includes first and second outer surface portions that are axially spaced apart from each other and which are both defined by the maximum outer diameter, and includes an undercut portion providing a central outer surface portion that is between the first and second outer surface portions, the undercut portion being defined by an undercut outer diameter, and wherein a ratio of the undercut outer diameter to the maximum outer diameter is between 0.8 and 1.0.
 6. The piston according to claim 5, wherein the cylindrical body is defined by a first length that is less than the overall length, and wherein a ratio of the first length to the maximum outer diameter is between 1.0 and 1.2.
 7. The piston according to claim 6, including a boss portion formed at the upstream end of the cylindrical body, the boss portion enclosing one end of the piston bore leaving an opposite end of the piston bore open to receive the spring assembly, and wherein the boss portion comprises a seat for a pivoting half ball, the seat comprising a conical surface formed within the boss portion and being defined by a conical angle, and wherein the conical angle is within a range between 100 and 120 degrees.
 8. The piston according to claim 5, including a boss portion formed at the upstream end of the cylindrical body, the boss portion enclosing one end of the piston bore leaving an opposite end of the piston bore open to receive the spring assembly, and wherein the boss portion comprises a seat for a pivoting half ball and is defined by a boss outer diameter, and wherein the seat comprises a conical opening defined by a conical surface formed within the boss portion, and wherein the conical opening is defined by a depth extending from an apex of the conical surface to an end face of the boss portion, and wherein a ratio of the depth to the boss outer diameter is between 0.3 and 0.4.
 9. A piston for a valve comprising: a cylindrical body surrounding a center axis and defined by an overall length extending from an upstream end to a downstream end, wherein the cylindrical body has a piston bore configured to receive a spring assembly, and including a boss portion formed at the upstream end of the cylindrical body, the boss portion enclosing one end of the piston bore leaving an opposite end of the piston bore open to receive the spring assembly, and wherein the boss portion comprises a seat for a pivoting half ball, the seat comprising a conical surface formed within the boss portion, and wherein the boss portion is defined by a boss outer diameter, and wherein the seat comprises a conical opening defined by the conical surface, and wherein the conical opening is defined by a depth extending from an apex of the conical surface to an end face of the boss portion, and wherein a ratio of the depth to the boss outer diameter is between 0.3 and 0.4.
 10. The piston according to claim 9, wherein the conical surface is defined by a conical angle, and wherein the conical angle is within a range between 100 and 120 degrees.
 11. The piston according to claim 9, wherein the cylindrical body has a maximum outer diameter that comprises a closure sleeve contact surface, and wherein the cylindrical body is defined by a first length that is less than the overall length, and wherein a ratio of the first length to the maximum outer diameter is between 1.0 and 1.2.
 12. The piston according to claim 9, wherein the cylindrical body portion has a maximum outer diameter that comprises a closure sleeve contact surface, and wherein the cylindrical body includes first and second outer surface portions that are axially spaced apart from each other and which are both defined by the maximum outer diameter, and includes an undercut portion providing a central outer surface portion that is between the first and second outer surface portions, the undercut portion being defined by an undercut outer diameter, and wherein a ratio of the undercut outer diameter to the maximum outer diameter is between 0.8 and 1.0.
 13. A piston and closure sleeve assembly for a valve comprising: a closure sleeve comprising a sleeve body surrounding a center axis and defined by an overall length extending from an upstream end to a downstream end, wherein the sleeve body has an internal cavity that is enclosed at the downstream end and open at the upstream end, and wherein the internal cavity is defined in part by a piston contact surface that is defined by an inner diameter, and wherein the sleeve body includes at least one damping orifice defined by a damping orifice diameter; and a piston comprising a cylindrical body surrounding a center axis and defined by an overall length extending from an upstream end to a downstream end, wherein the cylindrical body has a piston bore configured to receive a spring assembly, and wherein the cylindrical body has a maximum outer diameter that comprises a closure sleeve contact surface that slides against the piston contact surface, and wherein the cylindrical body includes at least one vent window defined by a vent window diameter, and wherein a ratio of the damping orifice diameter to the vent window diameter is between 0.375 and 0.450.
 14. A high pressure relief valve comprising: a valve housing defining an internal bore and having a valve inlet configured to be in fluid communication with a pump outlet; a closure sleeve at least partially received within the internal bore, the closure sleeve comprising a sleeve body surrounding a center axis, wherein the sleeve body has an internal cavity that is enclosed at the downstream end and open at the upstream end; a piston received within the internal cavity, wherein the internal cavity is defined in part by a piston contact surface, and wherein the piston comprises a cylindrical body surrounding a center axis and defined by an overall length extending from an upstream end to a downstream end, wherein the cylindrical body has a piston bore configured to receive a spring assembly, and wherein the cylindrical body has a maximum outer diameter that comprises a closure sleeve contact surface; a nozzle received within the internal bore of the valve housing and including a nozzle bore having a nozzle inlet in fluid communication with the valve inlet and a nozzle outlet; a spring assembly that biases the piston to close the nozzle outlet, and wherein when a system pressure at the nozzle outlet exceeds a predetermined pressure level, a spring biasing load is overcome to open the nozzle outlet to fluidly connect the nozzle to the internal cavity of the closure sleeve; and wherein the high pressure relief valve includes one or more of the following valve characteristics wherein the cylindrical body portion is defined by a first length that is less than the overall length, and wherein a ratio of the first length to the maximum outer diameter is between 1.0 and 1.2, wherein the cylindrical body includes first and second outer surface portions that are axially spaced apart from each other and which are both defined by the maximum outer diameter, and including an undercut portion providing a central outer surface portion that is between the first and second outer surface portions, the undercut portion being defined by an undercut outer diameter, and wherein a ratio of the undercut outer diameter to the maximum outer diameter is between 0.8 and 1.0, wherein the piston includes a boss portion formed at the upstream end of the cylindrical body, the boss portion enclosing one end of the piston bore leaving an opposite end of the piston bore open to receive the spring assembly, and wherein the boss portion comprises a seat for a pivoting half ball, the seat comprising a conical surface formed within the boss portion and being defined by a conical angle, and wherein the conical angle is within a range between 100 and 120 degrees, wherein the boss portion is defined by a boss outer diameter, and wherein the seat comprises a conical opening defined by the conical surface, and wherein the conical opening is defined by a depth extending from an apex of the conical surface to an end face of the boss portion, and wherein a ratio of the depth to the boss outer diameter is between 0.3 and 0.4, wherein the sleeve body includes at least one damping orifice defined by a damping orifice diameter, and wherein the cylindrical body of the piston includes at least one vent window defined by a vent window diameter, and wherein a ratio of the damping orifice diameter to the vent window diameter is between 0.375 and 0.450.
 15. A fuel supply system incorporating: a fuel pump having a pump inlet and a pump outlet, the pump inlet being in fluid communication with a fuel supply; a metering valve receiving fuel from the fuel pump and directing the fuel to a gas turbine engine; and a high pressure relief valve upstream of the metering valve and downstream of the pump inlet, the high pressure relief valve being configured to move to an open position once system pressure downstream of the pump outlet exceeds a predetermined pressure level such the fuel can be returned to the pump inlet via the high pressure relief valve, and wherein the high pressure relief valve comprises a valve housing defining an internal bore and having a valve inlet configured to be in fluid communication with a pump outlet; a closure sleeve at least partially received within the internal bore, the closure sleeve comprising a sleeve body surrounding a center axis, wherein the sleeve body has an internal cavity that is enclosed at the downstream end and open at the upstream end; a piston received within the internal cavity, wherein the internal cavity is defined in part by a piston contact surface, and wherein the piston comprises a cylindrical body surrounding a center axis and defined by an overall length extending from an upstream end to a downstream end, wherein the cylindrical body has a piston bore configured to receive a spring assembly, and wherein the cylindrical body has a maximum outer diameter that comprises a closure sleeve contact surface; a nozzle received within the internal bore of the valve housing and including a nozzle bore having a nozzle inlet in fluid communication with the valve inlet and a nozzle outlet; a spring assembly that biases the piston to close the nozzle outlet, and wherein when a system pressure at the nozzle outlet exceeds a predetermined pressure level, a spring biasing load is overcome to open the nozzle outlet to fluidly connect the nozzle to the internal cavity of the closure sleeve; and wherein the high pressure relief valve includes one or more of the following valve characteristics wherein the cylindrical body is defined by a first length that is less than the overall length, and wherein a ratio of the first length to the maximum outer diameter is between 1.0 and 1.2, wherein the cylindrical body includes first and second outer surface portions that are axially spaced apart from each other and which are both defined by the maximum outer diameter, and including an undercut portion providing a central outer surface portion that is between the first and second outer surface portions, the undercut portion being defined by an undercut outer diameter, and wherein a ratio of the undercut outer diameter to the maximum outer diameter is between 0.8 and 1.0, wherein the piston includes a boss portion formed at the upstream end of the cylindrical body, the boss portion enclosing one end of the piston bore leaving an opposite end of the piston bore open to receive the spring assembly, and wherein the boss portion comprises a seat for a pivoting half ball, the seat comprising a conical surface formed within the boss portion and being defined by a conical angle, and wherein the conical angle is within a range between 100 and 120 degrees, wherein the boss portion is defined by a boss outer diameter, and wherein the seat comprises a conical opening defined by the conical surface, and wherein the conical opening is defined by a depth extending from an apex of the conical surface to an end face of the boss portion, and wherein a ratio of the depth to the boss outer diameter is between 0.3 and 0.4, wherein the sleeve body includes at least one damping orifice defined by a damping orifice diameter, and wherein the cylindrical body of the piston includes at least one vent window defined by a vent window diameter, and wherein a ratio of the damping orifice diameter to the vent window diameter is between 0.375 and 0.450.
 16. A method of installing a component in a high pressure relief valve including the steps of: removing a piston from a valve housing and replacing the removed piston with a replaced piston, wherein a closure sleeve is at least partially received within the valve housing and includes an internal cavity that is enclosed at a downstream end and open at an upstream end, the piston is received within the internal cavity of the closure sleeve, and wherein the piston comprises a cylindrical body surrounding a center axis and defined by an overall length extending from an upstream end to a downstream end, wherein the cylindrical body has a piston bore configured to receive a spring assembly, and wherein the cylindrical body has a maximum outer diameter that comprises a closure sleeve contact surface; and wherein if the piston is removed and replaced, the replaced piston has one or more of the following piston characteristics wherein the cylindrical body is defined by a first length that is less than the overall length, and wherein a ratio of the first length to the maximum outer diameter is between 1.0 and 1.2, wherein the cylindrical body includes first and second outer surface portions that are axially spaced apart from each other and which are both defined by the maximum outer diameter, and including an undercut portion providing a central outer surface portion that is between the first and second outer surface portions, the undercut portion being defined by an undercut outer diameter, and wherein a ratio of the undercut outer diameter to the maximum outer diameter is between 0.8 and 1.0, wherein the piston includes a boss portion formed at the upstream end of the cylindrical body, the boss portion enclosing one end of the piston bore leaving an opposite end of the piston bore open to receive the spring assembly, and wherein the boss portion comprises a seat for a pivoting half ball, the seat comprising a conical surface formed within the boss portion and being defined by a conical angle, and wherein the conical angle is within a range between 100 and 120 degrees, wherein the boss portion is defined by a boss outer diameter, and wherein the seat comprises a conical opening defined by the conical surface, and wherein the conical opening is defined by a depth extending from an apex of the conical surface to an end face of the boss portion, and wherein a ratio of the depth to the boss outer diameter is between 0.3 and 0.4. 